OVERVIEW: The goal of the Imaging and Photomanipulation Initiative (I&PI) is to develop technologies for measuring and perturbing the localized activities that mediate and regulate cell migration and to use these technologies to make quantitative measurements for modeling cell migration. The emerging experimental paradigm is to initially detect and quantify local molecular events in migrating cells and then to manipulate such events by local activation or inactivation and assess the consequences on the migratory process. The Initiative has made great progress in developing the chemical and physical technologies and reagents to implement this paradigm. The goals for the next granting period are not only to continue developing these technologies, but also to use them on prototypical migration phenomena to develop working paradigms for studying cellular processes that are tightly regulated both spatially and temporally. The objectives of the I&PI are to: (1) develop and test, in cell cultures, in micro-patterned cell cultures, and tissues, new biosensors and probes both for local photoactivation and local photoinactivation, using chromophore assisted laser inactivation (CALI);(2) continue development of correlation methods for measuring molecular interactions, concentrations and dynamics both in vitro and in tissues;and, (3) use the advances provided in objectives (1) and (2) to develop data useful for modeling migration phenomena by investigators both inside and outside the Consortium.